Former opposition lawmaker “Long Hair” Leung Kwok-hung may walk free from a contempt of Legislative Council charge over his snatching of documents from a government official, after a Hong Kong court ruled that lawmakers are protected from such prosecution.

The West Kowloon Court sided with the defence in ruling that Leung’s actions against then undersecretary for development Eric Ma Siu-cheung were within the privileges offered by the Legislative Council (Powers and Privileges) Ordinance.

Leung, 61, has pleaded not guilty to a summons of contempt under the ordinance. It is alleged that Leung created a disturbance during a Legco committee meeting on November 15, 2016, causing it to be interrupted or likely to be interrupted.

Prosecutors said Leung approached Ma to borrow his folder and did not return it when asked to do so by committee chairwoman Alice Mak Mei-kuen.

Acting principal magistrate Ada Yim Shun-yee said on Monday: “The absolute privilege of free speech and debate enjoyed by Legco applies to individual members, as Legco can only function through its members and any attempt to limit the privilege by an offence of contempt might cause a chilling effect and should be taken cautiously.”

She also noted that Legco is “well capable to control and penalise, if it so wishes, any disturbance created by its members during the proceedings to uphold its dignity, where the situation calls for it, without external assistance”.

Courts and Legco would have overlapping jurisdiction over members’ misconduct only when their actions amounted to an ordinary criminal offence such as assault, criminal damage, criminal intimidation, blackmail or theft, she said.

Leung threw his fist in the air upon hearing the ruling.

“I believe in logic, so I think it’s very logical,” he told reporters outside court. “I must emphasise that the prosecution itself is a paradox.”

The case is believed to be the first time since the ordinance’s enactment in 1985 that a Legco member has been prosecuted under its Section 17c, which directly penalises interruptions of Legco sittings.

Prosecutors have until March 16 to decide if they will appeal against the ruling or drop the prosecution. Acting senior assistant director of public prosecutions Derek Lai Kim-wah said: “We need to consider the reasons for the ruling and decide the way forward.”

At the meeting where the drama unfolded government officials, including Ma, came under fire for not answering questions relating to Arup, an engineering consultancy firm.

The government commissioned Arup in March 2016 to do a study on a public housing project in Wang Chau, Yuen Long. The Development Bureau later found the firm to have leaked confidential internal data in a separate application on behalf of property conglomerate New World Development to build a private residential development in Wing Ning Tsuen, next to the Wang Chau project.